On Wed, 2003-12-10 at 10:34, Göran Broström wrote: > I recently ran into the following: > > > x <- c(1,2,4,3) > > lm(x ~ 1:length(x)) > Error in model.frame(formula, rownames, variables, varnames, extras, extranames, : > variable lengths differ > > but > > > lm(x ~ c(1:length(x))) > > Call: > lm(formula = x ~ c(1:length(x))) > > Coefficients: > (Intercept) c(1:length(x)) > 0.5 0.8 > > and > > > identical(1:4, c(1:4)) > [1] TRUE > > Should I report this as a bug?
No. In a formula ":" is interpreted differently. It is used to represent interactions. See help(formula). It is probably good practice to generate variables outside of the formula and then refer to them by name. Martyn ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
